This invention relates to a sifting machine having a sieve screen which can be caused to vibrate by vibration generators.
Among the known sifting machines of this type which are constructed in the form of vibrating or swinging sieves, there exists the drawback that the vibrations acting on the sieve screen are uniform and offer no possibilities for variation except in intensity. Since the energy imparted by the vibration generators generally acts on the material to be sifted as a reciprocable pushing sifting movement, in conformance with the classical sifting movement, the separating effect is often unsatisfactory.